campus design eng

8/9/2019 Campus Design Eng

http://slidepdf.com/reader/full/campus-design-eng 1/55

1

UTC-N

Overview of Campus NetworksOverview of Campus Networks DesignDesign



2

Overview

Read Chapter 1 for further information andexplanations

Much of the information in this chapter will

become clearer throughout the semester as

this chapter is meant to introduce you to someof the topics we will be discussing later

!he design models used in this chapter is not a

template for network design "t should be used

as a foundation for discussion of concepts and

a vehicle for addressing various issues



3

Icons

Multilayer Switch with Route Processor

- Don’t let the location of the links into this

icon confuse you. This will become clearer

when we configure this device.

igh-!nd Switch

Router

"orkgrou# Switch



4

Traditional Campus Networks



5

Traditional Campus Networks

Campus Network

# building or group of buildings connected into one

enterprise network that consists of or more $#Ns

!he company usually owns the physical wires

deployed in the campus

%enerally uses $#N technologies

%enerally deploy a campus design that is optimi&ed

for the fastest functional architecture over existing

wire



6

Traditional Campus NetworksNetwork #dministrator Challenges

$#N run effectively and efficiently #vailability and performance impacted by the amount of

bandwidth in the network

'nderstand( implement and manage traffic flow

Current "ssues

)roadcasts* "+ #R+ re,uests

-merging "ssues

Multicast traffic .traffic propagated to a specific group ofusers on a subnet/( video conferencing( multimedia traffic

0ecurity and traffic flow



#

ollow the 23453 rule( not the 53423

!raditional 53423 rule

6 537 traffic local to subnet( 237 remote

8Remote9 traffic 6 !raffic across the backbone or core to enterprise servers(

"nternet( remote sites( other subnets .more coming/



$

New 23453 rule

6 237 traffic local to subnet( 537 remote

!raffic moving towards new 23453 rule due to*

6 :eb based computing

6 0ervers consolidation of enterprise and workgroup servers intocentrali&ed server farms due to reduced !CO( security andease of management



1%

New Campus Model services can be

separated into categories*

6 $ocal

6 Remote

6 -nterprise



11

Traditional &outer and 'u( Campus



12

)irtual !"N *)!"N+ Tec,nolo-ies

Many of these diagrams have further explanations that

follow Much of this should be review from C"0 15;( but

will also be covered in much more detail later on this

semester Read on your own $ink at end of presentation



13

(FYI: Review) One of the technologies developed to

enable campus<wide =$#Ns is =$#N trunking #

=$#N trunk between two $ayer 2 switches allows

traffic from several logical networks to be multiplexed # =$#N trunk between a $ayer 2 switch and a router

allows the router to connect to several logical

networks over a single physical interface "n igure 2(

a =$#N trunk allows server > to talk to all the =$#Nssimultaneously !he yellow lines in igure 1 are "nter<

0witch $ink ."0$/ trunks that carry the pink( purple(

and green =$#Ns

5321, is a =$#N tagging protocol that wasdeveloped to allow =$#N trunking !he =$#N tag is

an integer incorporated into the header of frames

passing between two devices !he tag value allows

the data from multiple =$#Ns to be multiplexed and

demultiplexed



14

Traditional Campus./ide )!"N 0esi-n



15

(FYI: Review) $ayer 2 switching is used in the access(

distribution( and core layers our workgroups

represented by the colors blue( red( purple( and green

are distributed across several access<layer switchesConnectivity between workgroups is by Router > that

connects to all four =$#Ns $ayer ; switching and

services are concentrated at Router > -nterprise

servers are shown behind the router on different logical

networks indicated by the black lines

!he various =$#N connections to Router > could be

replaced by an "0$ trunk "n either case( Router > is

typically referred to as a ?router on a stick? or a ?one<

armed router? More routers can be used to distribute

the load( and each router attaches to several or all

=$#Ns !raffic between workgroups must traverse the

campus in the source =$#N to a port on the gateway

router( then back out into the destination =$#N



16

ultilayer Campus 0esi-n wit, ultilayer witc,in-

*witc, locks+



17

(FYI: Review) )ecause $ayer ; switching is used in the

distribution layer of the multilayer model( this is where

many of the characteristic advantages of routing apply

!he distribution layer forms a broadcast boundary so thatbroadcasts don@t pass from a building to the backbone or

vice<versa =alue<added features of the Cisco "O0

software apply at the distribution layer or example( the

distribution<layer switches cache information about Novell

servers and respond to %et Nearest 0erver ,ueries from

Novell clients in the building #nother example is

forwarding Dynamic Aost Configuration +rotocol .DAC+/

messages from mobile "+ workstations to a DAC+ server



1#

ultilayer odel wit, erver arm



1$

&edundant ultilayer Campus 0esi-n .0witch )locks/



2%

witc,in- $ayer 2 0witching

6 0witches based on M#C address

6 8hardware based bridging9 6 edge of the network .new campus mode/

$ayer ; 0witching

6 0witching at $2( hardware<based routing at $;

$ayer B 0witching 6 0witching at $2( hardware<based routing at $;( with

decisions optionally made on $B information .portnumbers/

6 orwarding decisions based on M#C address( "+address( and port numbers

6 Aelp control traffic based on O0 #0"C .#pplication<specific "ntegrated Circuit/

6 0peciali&ed hardware that handles frame forwarding in the

switch



21

&outer versus witc,

Router typically performs software<

based packet switching .process of

looking it up first in the routing tables/ 0witch typically performs hardware<

based frame switching .#0"C/



22

!ayer 2 witc,in-



23

!ayer 3 witc,in- Aardware<based routing



24

!ayer 4 witc,in-



25

! *ulti.!ayer witc,in-+



26

!

CiscoE speciali&ed form of switching androuting( not generic $; routing4$2

switching

Multilayer 0witches can operate at$ayers 2( ;( and B

cannot be performed using our CCN+

lab e,uipment .Catalyst B33F switchesand 2F23 routers/

8route once( switch many9



27

!

sometimes referred to as 8route once( switch

many9 .later/



2#

3.!ayer 'ierarc,ical 0esi-n

odel



2$

3.!ayer 'ierarc,ical 0esi-n odel

!he devices andconcepts are slightly

different then the ;<layer

model used in 0em G

Routing

Conceptual onlyH

!here will be

contradictions and some

devices may be argued

as one type of device oranother



3%

Core !ayer "nternet

Remote 0ite

=arious options and

implementations possible



31

0ample ;<layer hierarchy" n t e r n e t

C o r e

C o r eC o r e

D i s t r i b u t i o n D i s t r i b u t i o n D i s t r i b u t i o n

# c c e s s# c c e s s

# c c e s s

# c c e s s # c c e s s # c c e s s

# c c e s s

# c c e s s

# c c e s s

# c c e s s

# c c e s s

R e m o t e 0 i t e )

R e m o t e 0 i t e C

# c c e s s

D i s t r i b u t i o n

# c c e s s

# c c e s s

R e m o t e 0 i t e ## c c e s s



32

Core !ayer

0witches packets as fast as possible

Considered the backbone of the network

0hould not perform packet manipulation

6 No #C$s 6 No routing .usually/

6 No trunking

6 =$#Ns terminated at distribution device



33

0istri(ution !ayer



34

0istri(ution

!ayer

!he distribution layer of the network divides the access andcore layers and helps to define and differentiate the core

6 Departmental or workgroup access

6 )roadcast4multicast domain definition

6 =$#N routing 6 #ny media transitions that need to occur

6 0ecurity

6 +acket manipulation occurs here



35

"ccess !ayer



36

"ccess

!ayer

!he access layer is the point at which local end users are allowed into

the network

6 0hared bandwidth

6 0witched bandwidth

6 M#C<layer filtering or 5321x 6 Microsegmentation

6 Remote users gain network access( =+N



37

uildin- locks

Network building blocks can be any one of the

following fundamental campus elements*

6 0witch block 6 Core block

Contributing variables

6 0erver block

6 :#N block

6 Mainframe block

6 "nternet connectivity



3#

uildin- locks

"nternet )lockcould also be

included



3$

witc, lock

Consists of both switch and router functions 6 #ccess $ayer .#$/

$2 devices .workgroup switches* Catalyst 2IF3(

2I33( ;G33>$/

6 Distribution $ayer .D$/ $24$; devices .multilayer switches* Catalyst

BG33( FG33/

$2 and separate $; device .Catalyst ;F33>$

with 2533 series router<on<a<stick( etc/

Multiple D$ devices shown for loadbalancing and redundancy !his

may not be the case in many

networks



4%

AL – Access Layer

6 $2 switches in the wiring closets connect users to

the network at the access layer and provide

dedicated bandwidth to each port DL – Distribution Layer

6 $24$; switch4routers provide broadcast control(

security and connectivity for each switch block

witc, lock



41

#$ devices merge into one or more D$ devices

$2 #$ devices have redundant connections to the D$

device to maintain resiliency

6 0panning<!ree +rotocol .0!+/ makes redundant

links possible

witc, lock ."!+rimary

)ackup



42

witc, lock

. 0!

!he D$ device*

6 a switch and external router or

6 a multilayer switch .Catalyst BG33/

6 provides $2 and $; services

6 shields the switch block against broadcast storms

.and $2 errors/



43

iin- t,e witc, lock



44

iin- t,e witc, lock

# switch block is too large if*

6 # traffic bottleneck occurs in the routers at

the distribution layer because of intensiveC+' processing resulting from policy<

based filters

6 )roadcast or multicast traffic slows down

the switches and routers



45

Core lock # core is re,uired when there are two or more switch

blocks( otherwise the core or backbone is between

the distribution switch and the perimeter router

!he core block is responsible for transferring cross<

campus traffic without any processor<intensive

operations #ll the traffic going to and from the switch blocks(

server blocks( the "nternet( and the wide<area

network must pass through the core



46

Core lock

Core Switches:

Catalyst FG33

Core )lock



47

Core lock

!raffic going from one switch block to another also

must travel through the core

!he core handles much more traffic than any otherblock

6 must be able to pass the traffic to and from the

blocks as ,uickly as possible



4#

Core lock

Cisco FG33 supports*

6 up to ;5B 134133 -thernet

6 1I2 133> ast -thernet 6 5 OC12 #!M

6 up to 1;3 %igabit -thernet ports

6 switching bandwidth up to 2GF %bps 6 scalable multilayer switching up to 1J3

Mpps



4$

Core lock

)ecause =$#Ns terminate at the distribution device(core links are not trunk links and traffic is routedacross the core

6 core links do not carry multiple =$#Ns per link One or more switches can make up a core subnet

6 a minimum of two devices must be present in thecore to provide redundancy



5%

Collapsed Core

Distribution and Core $ayer functions performed in the

same device



51

Collapsed

Core

consolidation of D$ and core<layer functions into onedevice

6 prevalent in small campus networks each #$ switch has a redundant link to the D$ switch -ach #$ switch may support more than one subnetK

however( all subnets terminate on $; ports on theD$4core switch



52

Redundant uplinks provide $2 resiliency between the #$ andD$ switches

6 0panning tree blocks the redundant links to prevent loops

Redundancy is provided at $ayer ; by the dual distributionswitches with Aot 0tandby Router +rotocol .A0R+/(providing transparent default gateway operations for "+.later/

Collapsed

Core



53

0ual Core



54

0ual

Core

necessary when two or more switch blocks exist andredundant connections are re,uired

provides two e,ual<cost paths and twice the bandwidth -ach core switch carries a symmetrical number of

subnets to the $; function of the D$ device -ach switch block is redundantly linked to both core

switches( allowing for two distinct( e,ual path links



C,oosin- a Cisco roduct

Lnow particularsH .Number and types ofports/

#ccess $ayer 0witches

6 2IF3( BG33 Distribution $ayer 0witches

6 2IF3%( FG33( ;JG3

Core $ayer 0witches 6 FG33

campus design eng

Documents